Effects of damping mechanisms on the seismic response of isolated structures

The efficiency of various dissipative mechanisms to protect structures from pulse-type and near-source ground motions is examined. It is shown that under such motions, the concept of equivalent linear damping has limited meaning. This is because the transient response of a structure is more sensitive to the nature of the dissipation mechanisms, rather than to the amount of energy dissipated per cycle. Subsequently, physically realizable cycloidal pulses are introduced, and their resemblance to recorded near-source ground motions is illustrated.